[PATCH bpf-next 0/5] Allow CONFIG_DEBUG_INFO_DWARF5=y + CONFIG_DEBUG_INFO_BTF=y

[PATCH bpf-next 0/5] Allow CONFIG_DEBUG_INFO_DWARF5=y + CONFIG_DEBUG_INFO_BTF=y

[Nathan Chancellor]

Hi all,

This series allows CONFIG_DEBUG_INFO_DWARF5 to be selected with
CONFIG_DEBUG_INFO_BTF=y by checking the pahole version.

The first four patches add CONFIG_PAHOLE_VERSION and
scripts/pahole-version.sh to clean up all the places that pahole's
version is transformed into a 3-digit form.

The fourth patch adds a PAHOLE_VERSION dependency to DEBUG_INFO_DWARF5
so that there are no build errors when it is selected with
DEBUG_INFO_BTF.

I build tested Fedora's aarch64 and x86_64 config with ToT clang 14.0.0
and GCC 11 with CONFIG_DEBUG_INFO_DWARF5 enabled with both pahole 1.21
and 1.23.

Nathan Chancellor (5):
  MAINTAINERS: Add scripts/pahole-flags.sh to BPF section
  kbuild: Add CONFIG_PAHOLE_VERSION
  scripts/pahole-flags.sh: Use pahole-version.sh
  lib/Kconfig.debug: Use CONFIG_PAHOLE_VERSION
  lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+

 MAINTAINERS               |  2 ++
 init/Kconfig              |  4 ++++
 lib/Kconfig.debug         |  6 +++---
 scripts/pahole-flags.sh   |  2 +-
 scripts/pahole-version.sh | 13 +++++++++++++
 5 files changed, 23 insertions(+), 4 deletions(-)
 create mode 100755 scripts/pahole-version.sh


base-commit: 533de4aea6a91eb670ff8ff2b082bb34f2c5d6ab
-- 
2.35.1

[PATCH bpf-next 1/5] MAINTAINERS: Add scripts/pahole-flags.sh to BPF section

[Nathan Chancellor]

Currently, scripts/pahole-flags.sh has no formal maintainer. Add it to
the BPF section so that patches to it can be properly reviewed and
picked up.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 0d7883977e9b..0d422452c8ff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3523,6 +3523,7 @@ F:	net/sched/act_bpf.c
 F:	net/sched/cls_bpf.c
 F:	samples/bpf/
 F:	scripts/bpf_doc.py
+F:	scripts/pahole-flags.sh
 F:	tools/bpf/
 F:	tools/lib/bpf/
 F:	tools/testing/selftests/bpf/
-- 
2.35.1

[PATCH bpf-next 2/5] kbuild: Add CONFIG_PAHOLE_VERSION

[Nathan Chancellor]

There are a few different places where pahole's version is turned into a
three digit form with the exact same command. Move this command into
scripts/pahole-version.sh to reduce the amount of duplication across the
tree.

Create CONFIG_PAHOLE_VERSION so the version code can be used in Kconfig
to enable and disable configuration options based on the pahole version,
which is already done in a couple of places.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 MAINTAINERS               |  1 +
 init/Kconfig              |  4 ++++
 scripts/pahole-version.sh | 13 +++++++++++++
 3 files changed, 18 insertions(+)
 create mode 100755 scripts/pahole-version.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 0d422452c8ff..d8a66d50f224 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3524,6 +3524,7 @@ F:	net/sched/cls_bpf.c
 F:	samples/bpf/
 F:	scripts/bpf_doc.py
 F:	scripts/pahole-flags.sh
+F:	scripts/pahole-version.sh
 F:	tools/bpf/
 F:	tools/lib/bpf/
 F:	tools/testing/selftests/bpf/
diff --git a/init/Kconfig b/init/Kconfig
index e9119bf54b1f..7328d4f25370 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -86,6 +86,10 @@ config CC_HAS_ASM_INLINE
 config CC_HAS_NO_PROFILE_FN_ATTR
 	def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
 
+config PAHOLE_VERSION
+	int
+	default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
+
 config CONSTRUCTORS
 	bool
 
diff --git a/scripts/pahole-version.sh b/scripts/pahole-version.sh
new file mode 100755
index 000000000000..f8a32ab93ad1
--- /dev/null
+++ b/scripts/pahole-version.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Usage: $ ./pahole-version.sh pahole
+#
+# Prints pahole's version in a 3-digit form, such as 119 for v1.19.
+
+if [ ! -x "$(command -v "$@")" ]; then
+	echo 0
+	exit 1
+fi
+
+"$@" --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'
-- 
2.35.1

[PATCH bpf-next 3/5] scripts/pahole-flags.sh: Use pahole-version.sh

[Nathan Chancellor]

Use pahole-version.sh to get pahole's version code to reduce the amount
of duplication across the tree.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 scripts/pahole-flags.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
index e6093adf4c06..c293941612e7 100755
--- a/scripts/pahole-flags.sh
+++ b/scripts/pahole-flags.sh
@@ -7,7 +7,7 @@ if ! [ -x "$(command -v ${PAHOLE})" ]; then
 	exit 0
 fi
 
-pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
+pahole_ver=$($(dirname $0)/pahole-version.sh ${PAHOLE})
 
 if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then
 	# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
-- 
2.35.1

[PATCH bpf-next 4/5] lib/Kconfig.debug: Use CONFIG_PAHOLE_VERSION

[Nathan Chancellor]

Now that CONFIG_PAHOLE_VERSION exists, use it in the definition of
CONFIG_PAHOLE_HAS_SPLIT_BTF and CONFIG_PAHOLE_HAS_BTF_TAG to reduce the
amount of duplication across the tree.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 lib/Kconfig.debug | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6159859769fa..bd487d480902 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -323,10 +323,10 @@ config DEBUG_INFO_BTF
 	  DWARF type info into equivalent deduplicated BTF type info.
 
 config PAHOLE_HAS_SPLIT_BTF
-	def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
+	def_bool PAHOLE_VERSION >= 119
 
 config PAHOLE_HAS_BTF_TAG
-	def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "123")
+	def_bool PAHOLE_VERSION >= 123
 	depends on CC_IS_CLANG
 	help
 	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
-- 
2.35.1

[PATCH bpf-next 5/5] lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+

[Nathan Chancellor]

Commit 98cd6f521f10 ("Kconfig: allow explicit opt in to DWARF v5")
prevented CONFIG_DEBUG_INFO_DWARF5 from being selected when
CONFIG_DEBUG_INFO_BTF is enabled because pahole had issues with clang's
DWARF5 info. This was resolved by [1], which is in pahole v1.21.

Allow DEBUG_INFO_DWARF5 to be selected with DEBUG_INFO_BTF when using
pahole v1.21 or newer.

[1]: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=7d8e829f636f47aba2e1b6eda57e74d8e31f733c

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 lib/Kconfig.debug | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index bd487d480902..1555da672275 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -296,7 +296,7 @@ config DEBUG_INFO_DWARF4
 config DEBUG_INFO_DWARF5
 	bool "Generate DWARF Version 5 debuginfo"
 	depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
-	depends on !DEBUG_INFO_BTF
+	depends on !DEBUG_INFO_BTF || PAHOLE_VERSION >= 121
 	help
 	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
 	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
-- 
2.35.1

Re: [PATCH bpf-next 0/5] Allow CONFIG_DEBUG_INFO_DWARF5=y + CONFIG_DEBUG_INFO_BTF=y

[Andrii Nakryiko]

On Tue, Feb 1, 2022 at 12:56 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Hi all,
>
> This series allows CONFIG_DEBUG_INFO_DWARF5 to be selected with
> CONFIG_DEBUG_INFO_BTF=y by checking the pahole version.
>
> The first four patches add CONFIG_PAHOLE_VERSION and
> scripts/pahole-version.sh to clean up all the places that pahole's
> version is transformed into a 3-digit form.
>
> The fourth patch adds a PAHOLE_VERSION dependency to DEBUG_INFO_DWARF5
> so that there are no build errors when it is selected with
> DEBUG_INFO_BTF.
>
> I build tested Fedora's aarch64 and x86_64 config with ToT clang 14.0.0
> and GCC 11 with CONFIG_DEBUG_INFO_DWARF5 enabled with both pahole 1.21
> and 1.23.
>
> Nathan Chancellor (5):
>   MAINTAINERS: Add scripts/pahole-flags.sh to BPF section
>   kbuild: Add CONFIG_PAHOLE_VERSION
>   scripts/pahole-flags.sh: Use pahole-version.sh
>   lib/Kconfig.debug: Use CONFIG_PAHOLE_VERSION
>   lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+
>

LGTM. I'd probably combine patches 2 and 3, but it's minor. I really
like the CONFIG_PAHOLE_VERSION and how much cleaner it makes Kconfig
options.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

>  MAINTAINERS               |  2 ++
>  init/Kconfig              |  4 ++++
>  lib/Kconfig.debug         |  6 +++---
>  scripts/pahole-flags.sh   |  2 +-
>  scripts/pahole-version.sh | 13 +++++++++++++
>  5 files changed, 23 insertions(+), 4 deletions(-)
>  create mode 100755 scripts/pahole-version.sh
>
>
> base-commit: 533de4aea6a91eb670ff8ff2b082bb34f2c5d6ab
> --
> 2.35.1
>

Re: [PATCH bpf-next 0/5] Allow CONFIG_DEBUG_INFO_DWARF5=y + CONFIG_DEBUG_INFO_BTF=y

[Daniel Borkmann]

On 2/2/22 8:05 AM, Andrii Nakryiko wrote:
> On Tue, Feb 1, 2022 at 12:56 PM Nathan Chancellor <nathan@kernel.org> wrote:
>>
>> This series allows CONFIG_DEBUG_INFO_DWARF5 to be selected with
>> CONFIG_DEBUG_INFO_BTF=y by checking the pahole version.
>>
>> The first four patches add CONFIG_PAHOLE_VERSION and
>> scripts/pahole-version.sh to clean up all the places that pahole's
>> version is transformed into a 3-digit form.
>>
>> The fourth patch adds a PAHOLE_VERSION dependency to DEBUG_INFO_DWARF5
>> so that there are no build errors when it is selected with
>> DEBUG_INFO_BTF.
>>
>> I build tested Fedora's aarch64 and x86_64 config with ToT clang 14.0.0
>> and GCC 11 with CONFIG_DEBUG_INFO_DWARF5 enabled with both pahole 1.21
>> and 1.23.
>>
>> Nathan Chancellor (5):
>>    MAINTAINERS: Add scripts/pahole-flags.sh to BPF section
>>    kbuild: Add CONFIG_PAHOLE_VERSION
>>    scripts/pahole-flags.sh: Use pahole-version.sh
>>    lib/Kconfig.debug: Use CONFIG_PAHOLE_VERSION
>>    lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+
>>
> 
> LGTM. I'd probably combine patches 2 and 3, but it's minor. I really
> like the CONFIG_PAHOLE_VERSION and how much cleaner it makes Kconfig
> options.

+1, thanks for working on getting this enabled! I think patches 2 and 3 are
rather logically separate, so as-is is fine as well imho. Applied, thanks!

Re: [PATCH bpf-next 0/5] Allow CONFIG_DEBUG_INFO_DWARF5=y + CONFIG_DEBUG_INFO_BTF=y

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Tue,  1 Feb 2022 13:56:19 -0700 you wrote:
> Hi all,
> 
> This series allows CONFIG_DEBUG_INFO_DWARF5 to be selected with
> CONFIG_DEBUG_INFO_BTF=y by checking the pahole version.
> 
> The first four patches add CONFIG_PAHOLE_VERSION and
> scripts/pahole-version.sh to clean up all the places that pahole's
> version is transformed into a 3-digit form.
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/5] MAINTAINERS: Add scripts/pahole-flags.sh to BPF section
    https://git.kernel.org/bpf/bpf-next/c/f67644b4f282
  - [bpf-next,2/5] kbuild: Add CONFIG_PAHOLE_VERSION
    https://git.kernel.org/bpf/bpf-next/c/613fe1692377
  - [bpf-next,3/5] scripts/pahole-flags.sh: Use pahole-version.sh
    https://git.kernel.org/bpf/bpf-next/c/2d6c9810eb89
  - [bpf-next,4/5] lib/Kconfig.debug: Use CONFIG_PAHOLE_VERSION
    https://git.kernel.org/bpf/bpf-next/c/6323c81350b7
  - [bpf-next,5/5] lib/Kconfig.debug: Allow BTF + DWARF5 with pahole 1.21+
    https://git.kernel.org/bpf/bpf-next/c/42d9b379e3e1

You are awesome, thank you!
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